1. Field of the Invention
The present invention relates to a manufacturing method of a silicon-on-insulator (SOI) substrate having a so-called SOI structure in which a single crystal semiconductor layer is provided on an insulating surface, and a manufacturing method of a semiconductor device having the SOI structure.
2. Description of the Related Art
Integrated circuits have been developed, in which a semiconductor substrate called a silicon-on-insulator (hereinafter also referred to as “SOI”) having a thin single crystal semiconductor layer on an insulating surface is used instead of a silicon wafer manufactured in such a manner that an ingot of a single crystal semiconductor is thinly sliced. An integrated circuit using an SOI substrate has been attracting attention because parasitic capacitance between a drain of a transistor and the substrate is reduced and the performance of the semiconductor integrated circuit is improved.
As a manufacturing method of an SOI substrate, a hydrogen ion implantation separation method is known (for example, see Patent Document 1: Japanese Published Patent Application No. 2000-124092). The hydrogen ion implantation separation method is a method in which hydrogen ions are implanted into a silicon wafer to form a damaged region at a predetermined depth from a surface of the silicon wafer, the silicon wafer is separated at the damaged region, whereby a thin silicon layer is bonded to another silicon wafer. It is necessary that, in addition to heat treatment for separating a silicon layer, heat treatment under an oxidation atmosphere be performed to form an oxide film over the silicon layer, the oxide layer be removed, and heat treatment at 1000° C. to 1300° C. be performed to increase bonding strength.
Meanwhile, a semiconductor device in which an insulating substrate such as a substrate made of high heat resistance glass is provided with a silicon layer is disclosed (for example, see Patent Document 2: Japanese Published Patent Application No. H11-163363). In this semiconductor device, an entire surface of crystallized glass whose strain point is greater than or equal to 750° C. is protected by an insulating silicon film, and a silicon layer obtained by a hydrogen ion implantation separation method is bonded to the insulating silicon film.